Slag is a product which is essentially generated in a steel smelting process. Slag is essentially produced from the gangue components of iron ore or coke in an iron making process, or from oxides obtained upon oxidation and deoxidation of molten iron or molten steel in a steel making process or from side materials, etc., added for refining.
Slag, which is composed mainly of SiO2 and CaO, includes Al2O3, FeO, MgO, P2O5 and CaS, depending on the type of refining reaction.
Iron making slag is composed mainly of CaO—SiO2—Al2O3, and steel making slag based on oxidation of molten iron or molten steel is composed mainly of CaO—SiO2—FeO.